1. Field of the Invention
The present invention relates to an information processing apparatus for sending data to an output device, such as a printer, which is connected through a bidirectional interface.
2. Related Background Art
Conventionally, a printer which is connected to a host computer through an interface (e.g., a Centronics interface) analyzes input data from the host computer and develops bit-map data as output data of, e.g., a laser beam printer. The printer then scan-exposes a photosensitive drum with a laser beam modulated on the basis of this developed data, thereby outputting image data.
In the case of a printer with an emulation function, a plurality of printer control language systems (command systems) can be processed; the printer can execute printing while switching an emulation mode and a native mode in accordance with application programs that a user executes. The printer of this type has switches for switching programs for interpreting the printer control languages and card slots for giving switching designation.
The printer of the above type, however, has no function of checking compatibility of a language environment, which is preset in the printer, before starting printing. Therefore, if printing is started by transferring print data to the printer notwithstanding that the language environment preset in the printer differs from the language environment that an application has set, unexpected results are printed.
As described above, under a print system environment in which printer control languages are selectively used (i.e., an environment in which a plurality of printer drivers can be selectively executed), a printer control language to be used is determined in accordance with a hardware environment set by a user. Therefore, if the printer control language environments of a host computer and a printer do not match each other, a printing failure occurs because there is no relieving means for obtaining matching. When the printer is located apart from the host computer and print data with a large number of pages is processed, a user does not notice the situation at once, resulting in a serious problem of waste of a paper resource due to unnecessary printing.
In addition, in switching between the language environments as described above, if a memory environment is freed, the contents (forms, user fonts, and the memory setting of a RAM) set in a memory of a printer are erased by rewriting. Therefore, even when the same language environment is selected again, not only the information about the forms, the user fonts, and the like but the memory map of the RAM cannot be reproduced correctly. This makes it impossible to ensure the printing under the environmental status before the switching.
If, on the other hand, the memory environment is controlled in such a manner as to keep the status before the language environments are switched, a memory space usable after the switching is rather limited. This significantly decreases the recording efficiency in the environment after the switching.